Search

Vertical drains can be installed in square and triangular patterns. Which pattern is better?

Vertical drains are commonly installed in square and triangular patterns. The zone of influence of vertical drains (R) is a function of drain spacing (S).

For drains in square pattern: R = 0.546S
For drains in triangular pattern: R = 0.525S

Continue Reading »

Filed under Marine Works | 0 Comments

What is the purpose of providing shoes in prefabricated drains?

Shoes are normally installed in prefabricated drains for the following reasons:

(i) It avoids the entry of soils into the mandrel by sealing it during the installation of drains.

(ii) It performs like an anchor to retain the drains at the designed depth and to stop the drains from being pulled out during the withdrawn of mandrels after driving the mandrels into ground.

Continue Reading »

Filed under Marine Works | 0 Comments

What are the considerations in selecting marine plants and land plants for installation of band drains?

For installation of band drains by marine plants, it must have sufficient water depth to accommodate the marine plants in the first place. However, due to the effect of tides and waves, the establishment of the position for installation of band drains and the subsequent installation works may be affected. In addition, the establishment cost of marine plants is higher than that of land plants.

Continue Reading »

Filed under Marine Works | 0 Comments

For drained reclamation, what is the significance of smear zone induced by installation of band drains?

During installation of band drains, smear zones are created in which a zone of soil surrounding the band drains are disturbed. The compressibility of surrounding soils is increased and it results in the reduction of their permeability.

Continue Reading »

Filed under Marine Works | 0 Comments

What are the potential problems of smear around vertical drains?

Smear zones are generated during the installation of vertical drains in which the zone of soils surrounding the band drains are disturbed. Soils in the smear zones are remoulded during the installation process and the effectiveness of band drains is reduced. For instance, the compressibility of surrounding soils is increased and this brings about the reduction of their permeability. In essence, with the reduced permeability of soils around band drains, it takes longer time to complete the consolidation process.

Continue Reading »

Filed under Marine Works | 0 Comments